1. Field of the Invention
The invention generally relates to testing technology, and more particularly, to the Digital Diagnostic Monitoring Interface (DDMI) calibration test of RX POWER.
2. Description of the Related Art
With the development of network technology, optical network technologies have seen more and more progress. Passive Optical Network (PON) is one of the important optical network technologies. Comparing with the traditional Point to Point (P2P) network structure for the optical terminal, the Passive Optical Network adopts Point to Multipoint (P2MP) network structure. In the Passive Optical Network, the Optical Line terminal (OLT) transmits data to many Optical Network Units (ONUs) through an Optical Splitter for reducing the requirement of the fiber and the optical elements. The Passive Optical Network technology comprises Ethernet Passive Optical Network (EPON) technology, Gigabit Passive Optical Network (GPON) technology, and so on.
The Gigabit Passive Optical Network technology is a standard which is specified by ITU-T. The Gigabit Passive Optical Network technology provides 2.5 Gbps bandwidth for single wavelength and the encapsulation method of the Gigabit Passive Optical Network technology provides an efficient and general mechanism to transmit different services, such as assigning the video, audio, image and other kinds of signals. In addition, the transmission convergence (TC) layer of the Gigabit Passive Optical Network is synchronous, and it uses the standard 8 kHz (1.25 us) frame to make sure Gigabit Passive Optical Network can directly support Time-Division Multiplex (TDM) service and that it is suitable for the transmission of the base station of the mobile network and the traditional dedicated line.
Therefore, how to increase the testing precision of the products of Gigabit Passive Optical Network is a subject worthy of attention.